/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2002 Xodnizel
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "mapinc.h"

#define mode mapbyte1[0]
#define page mapbyte1[1]

static uint32 Get8K(uint32 A) {
	uint32 bank;

	bank = (page << 2) | ((A >> 13) & 1);

	if (A & 0x4000 && !(mode & 1)) bank |= 0xC;
	if (!(A & 0x8000)) bank |= 0x20;
	if (mode == 2) bank |= 2;
	else bank |= (A >> 13) & 2;
	return(bank);
}

static void Synco(void) {
	uint32 x;
	if (mapbyte1[0] <= 2)
		MIRROR_SET2(1);
	else
		MIRROR_SET2(0);
	for (x = 0x6000; x < 0x10000; x += 8192)
		ROM_BANK8(x, Get8K(x));
}

static DECLFW(Write) {
	if (A & 0x8000) mapbyte1[1] = V & 0xF;
	else mapbyte1[0] = (mapbyte1[0] & 2) | ((V >> 1) & 1);

	if (A & 0x4000) mapbyte1[0] = (mapbyte1[0] & 1) | ((V >> 3) & 2);
	Synco();
}

void Mapper51_init(void) {
	SetWriteHandler(0x6000, 0xFFFF, Write);
	SetReadHandler(0x6000, 0xFFFF, CartBR);
	mapbyte1[0] = 1;
	mapbyte1[1] = 0;
	Synco();
}
